Space frames are well known and extensively used in the construction of buildings such as exhibition halls, theatres and the like where large areas are required to be covered, free of supporting columns. For such purposes, architects commonly favor space frames of the double-layer flat grid type, such a structure having an upper square grid assembly of chords spaced above a lower square grid assembly of chords, intersections of the upper and lower grids being interconnected by diagonal struts or web members so that the space frame consists of a combination of square-base pyramidal shapes.
The economy of space frames of this type is particularly sensitive to the cost of the nodal connections of the members comprising the grid. A variety of connector components have been devised for interconnecting: at each node of the structure, the chords and the diagonal struts.
A typical way to make a space frame is to fabricate members and joints as unique parts and bolt them together in the field. Some systems use pyramidal modules which are field assembled.
There are three main disadvantages to those systems:
1. Costs--Where you have separate nodes and many member connections, hardware costs are high.
2. Erection Time and Difficulty--The more pieces you have, the more field assembly time required.
3. Exposed Fasteners--They are unsightly and tend to corrode.